The present invention relates to a sliding gate valve for pouring molten metal, as for example, from the bottom of a receiving vessel such as a ladle or tundish. The valve of the invention includes a slide plate having at least one outlet port and being contained in a movable frame. The slide plate is spring-biased upwardly against a head plate located above the slide plate. The head plate contains an opening that communicates with the vessel interior and cooperates with that in the slide plate to pass molten metal from the receiving vessel when the openings are vertically aligned. The head plate is held by a mounting member connected to the bottom of the receiving vessel and the slide gate frame is held by a support device equipped with tensioning means for pressing the frame and its contained slide plate against the head plate.
In known sliding gate valves of the described type, the frame slides inside a housing forming part of the support device. Usually the housing is hinged to the mounting plate, and can be pressed against the mounting plate by means of suitable tensioning apparatus, including springs that are compressed between the frame and the slide plate, and thus force the slide plate up against the head plate. A pressure cylinder, operative to move the frame and slide plate relative to the head plate, laterally penetrates the housing to connect with the frame.
The use of an essentially closed housing as a support device has several disadvantages. A serious drawback is that even minor quantities of escaped liquid metal or other contaminants, for example, tar or sand, can obstruct the free motion of the relatively movable parts, so that the frame and the slide plate contained within it cannot be moved satisfactorily. The resultant operational disruptions can have far-reaching consequences. Furthermore, the fabrication and installation of the housing, the sliding members within it, and the pressure cylinder require considerable constructional effort and expense.
Therefore, it is the aim of the invention to further develop the above-described type of sliding gate valve in such a manner that the troublesome and structurally cumbersome housing is eliminated, and the drive for moving the frame is improved and simplified.